
[Federal Register Volume 77, Number 173 (Thursday, September 6, 2012)]
[Rules and Regulations]
[Pages 54798-54800]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-21289]



[[Page 54798]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1065; Directorate Identifier 2011-NM-007-AD; 
Amendment 39-17175; AD 2012-17-12]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
The Boeing Company Model 747-400 series airplanes. This AD was prompted 
by reports of water leaking into electrical and electronic equipment in 
the main equipment center (MEC). This AD requires modifying the floor 
panels; removing drains; installing floor supports, floor drain trough 
doublers, drain troughs, and drains; and sealing and taping the floor 
panels. We are issuing this AD to prevent water from entering the MEC, 
which could result in an electrical short and potential loss of several 
functions essential for safe flight.

DATES: This AD is effective October 11, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of October 11, 
2012.

ADDRESSES: For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; phone: 206-
544-5000, extension 1; fax: 206-766-5680; Internet: https://www.myboeingfleet.com. You may review copies of the referenced service 
information at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue SW., Renton, Washington. For information on the availability of 
this material at the FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (phone: 800-647-5527) is Document Management Facility, 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Francis Smith, Aerospace Engineer, 
Cabin Safety & Environmental Systems Branch, ANM-150S, Seattle Aircraft 
Certification Office (ACO), FAA, 1601 Lind Avenue SW., Renton, 
Washington 98057-3356; phone: 425-917-6596; fax: 425-917-6590; email: 
Francis.Smith@faa.gov.

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That NPRM was published in the Federal Register on October 11, 2011 (76 
FR 62667). That NPRM proposed to require modifying the floor panels; 
removing drains; installing floor supports, floor drain trough 
doublers, drain troughs, and drains; and sealing and taping the floor 
panels.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comment received on the proposal 
(76 FR 62667, October 11, 2011) and the FAA's response to each comment.

Concurrence With NPRM (76 FR 62667, October 11, 2011)

    Boeing stated that it has reviewed the NPRM (76 FR 62667, October 
11, 2011) and concurs with the contents of the proposed rule.

Request To Withdraw NPRM (76 FR 62667, October 11, 2011): Unsafe 
Condition Already Addressed

    UPS stated it believes the NPRM (76 FR 62667, October 11, 2011) is 
unnecessary and increases the economic burden on operators because the 
unsafe condition of water leaking into the MEC is already addressed in 
AD 2011-16-06, Amendment 39-16764 (76 FR 47427, August 5, 2011). UPS 
noted that an intact MEC drip shield should prevent water from leaking 
onto the electronic and electrical equipment, thereby eliminating the 
need for additional rulemaking.
    UPS also noted that it finds the NPRM (76 FR 62667, October 11, 
2011) problematic because it establishes an AD-mandated configuration 
for floor panel sealing in the nose section of Model 747-400BCF and 
747-400F airplanes that is different from the floor sealing criteria 
for the center and aft sections of the same airplanes.
    We do not agree with the request to withdraw the NPRM (76 FR 62667, 
October 11, 2011). While we recognize that most of the airplanes 
affected by this AD are also affected by AD 2011-16-06, Amendment 39-
16764 (76 FR 47427, August 5, 2011), water intrusion into the MEC 
addressed by the NPRM is in locations and by means different than those 
addressed by AD 2011-16-06. AD 2011-16-06 addresses water intrusion 
that migrates through cracked drip shields into the exhaust plenum and 
the MEC, and affects stations 117 and 118 for certain Model 747-400BCF 
and 747-400F airplanes. The NPRM addresses water intrusion through main 
deck panels, fasteners and floor fittings, and affects stations 210 and 
530 for certain Model 747-400BCF and -400F airplanes.
    We found the safety risk to be sufficient enough to require a 
specific floor sealing criteria to the affected areas. While a possible 
loss of uniform floor sealing criteria throughout the airplane may 
result, this AD action is necessary to adequately address the stated 
unsafe condition to the vulnerable areas. Operators seeking to 
establish more uniform floor panel sealing criteria may submit a 
request for an alternative method of compliance (AMOC) as specified in 
paragraph (h) of the AD. We have not changed the final rule in this 
regard.

Request To Withdraw NPRM (76 FR 62667, October 11, 2011): Low Risk of 
Water Intrusion

    In addition, UPS stated that the probability for water intrusion on 
the forward section of Model 747-400BCF airplanes is overstated because 
these models do not have a nose cargo door like Model 747-400F 
airplanes. Therefore, Model 747-400BCF airplanes are not as susceptible 
to moisture entering the forward area of the main deck cargo 
compartment during cargo loading in adverse weather conditions.
    We do not agree. Both water intrusion safety concerns were studied 
separately based on reports submitted from multiple operators. The data 
were reviewed based on the location and causes of the water intrusion. 
Based on the frequency of reported failures, severity of outcome, and 
airplane usage, both studies showed an unacceptable and unsafe 
condition if left uncorrected. Addressing only one source of water 
intrusion neither precludes nor diminishes the probability of the 
other. We have not changed the final rule in this regard.

[[Page 54799]]

Request To Withdraw NPRM (76 FR 62667, October 11, 2011): Revise 
Operational Procedures

    UPS also stated that proper ground operational procedures will 
significantly reduce water accumulation in the nose area, either 
through the main entry door or on pallets or containers.
    We infer that UPS requested withdrawal of the NPRM (76 FR 62667, 
October 11, 2011) in favor of revised ground operational procedures. We 
do not agree that revising operational procedures to avoid the 
identified unsafe condition is a consistent or reliable method in 
precluding what is inherently a safety risk through design. In 
determining a corrective action, Boeing and the FAA agreed that a 
design solution, instead of an operational solution, provides the best 
method to address the identified unsafe condition. No change to the 
final rule is necessary.

Request To Withdraw NPRM (76 FR 62667, October 11, 2011): Conflict With 
Aircraft Maintenance Manual (AMM)

    UPS also stated that Figures 18 and 23 of Boeing Special Attention 
Service Bulletin 747-25-3586, dated November 12, 2010, specify that 
different materials be used in lieu of those called out in Section 53-
21-02 of the Boeing Model 747-400 AMM. UPS stated that by not allowing 
operators to use the AMM, the NPRM (76 FR 62667, October 11, 2011) 
would put the UPS mechanics in an untenable situation. Mechanics 
following AMM procedures in the nose area of these two airplanes would 
unknowingly be altering an AD-mandated configuration.
    We do not agree because an AD-mandated configuration always takes 
precedence over AMMs. When there is a conflict between an AD 
requirement and service document, the operator must always comply with 
the requirements of the AD, as explicitly stated in the requirements of 
Federal Aviation Regulations 14 CFR 39.27. We have not changed the 
final rule in this regard.

Request To Allow Alternative Floor Sealing Procedures

    UPS noted that it and other operators have developed improved 
alternative floor panel sealing procedures based on years of 
operational experience with cargo aircraft. UPS stated that the NPRM 
(76 FR 62667, October 11, 2011) would mandate a Boeing floor sealing 
procedure that appears optimized for passenger aircraft flooring, which 
is not as effective as the procedures UPS uses today. UPS noted that 
this situation creates more of a regulatory problem with maintaining an 
AD-mandated condition than a safety of flight condition, as there are 
many ways to adequately seal the floor panels to prevent moisture 
intrusion. UPS noted that obtaining an alternative method of compliance 
(AMOC) approval for a floor sealing procedure presents another undue 
regulatory burden on operators.
    We recognize the different methods operators currently use for 
floor panel sealing procedures to mitigate this safety concern. 
However, the frequency of failures reported when using these different 
methods underscores the importance of providing an acceptable method 
for operators to follow in reducing the safety risk. Under the 
provisions of paragraph (h) of the final rule, we will consider 
requests for approval of an AMOC if sufficient data are submitted to 
substantiate that alternative method of sealing floor panels to prevent 
moisture intrusion would provide an acceptable level of safety. We have 
not changed the final rule in this regard.

Request for Revised Service Information

    UPS submitted the following list of technical errors found in 
Boeing Special Attention Service Bulletin 747-25-3586, dated November 
12, 2010, and requested that a revision to this service information be 
issued to address them.
     The fastener quantities specified in the fastener table in 
figure 7 are incorrect.
     Figure 17 specifies installing the modified floor panels 
with new fasteners, followed by figure 18, which specifies removing and 
reinstalling all floor panels between station 140 and station 640. 
Figure 18 should specify excluding those floor panels installed as 
shown in figure 17.
     Figure 8, Detail G, and figure 14, Detail K, should show 
the doubler and the support, not just the doubler.
    We acknowledge and agree that there are certain technical errors 
identified in the figures of Boeing Special Attention Service Bulletin 
747-25-3586, dated November 12, 2010. We have contacted Boeing and it 
has acknowledged the list of technical issues identified. We consider 
Boeing Special Attention Service Bulletin 747-25-3586, dated November 
12, 2010, adequate to address the identified unsafe condition; and this 
service information was validated by Boeing on an airplane. Different 
operators may see different numbers of necessary fasteners and will 
have to submit an AMOC if their configuration deviates from Boeing 
Special Attention Service Bulletin 747-25-3586, dated November 12, 
2010, instructions. Boeing stated it will address the issues in a 
Boeing service bulletin revision or other service document to provide 
clarity in the work steps. We have not changed the final rule in this 
regard.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD as proposed.

Costs of Compliance

    We estimate that this AD affects 12 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
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                                                                                                Cost on U.S.
              Action                    Labor cost        Parts cost    Cost per product          operators
----------------------------------------------------------------------------------------------------------------
Floor panel reworking and          Up to 644 work-hours      $64,033  Up to $118,773......  Up to $1,425,276.
 sealing; installing drains,        x $85 per hour =
 drain trough doublers, and drain   $54,740.
 troughs.
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    According to the manufacturer, some of the costs of this AD may be 
covered under warranty, thereby reducing the cost impact on affected 
individuals. We do not control warranty coverage for affected 
individuals. As a result, we have included all costs in our cost 
estimate.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.

[[Page 54800]]

    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2012-17-12 The Boeing Company: Amendment 39-17175; Docket No. FAA-
2011-1065; Directorate Identifier 2011-NM-007-AD.

(a) Effective Date

    This AD is effective October 11, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 747-400 series 
airplanes, certificated in any category, as identified in Boeing 
Special Attention Service Bulletin 747-25-3586, dated November 12, 
2010.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 25, Equipment and Furnishings.

(e) Unsafe Condition

    This AD was prompted by reports of water leaking into electrical 
and electronic equipment in the main equipment center. We are 
issuing this AD to prevent water from entering the main equipment 
center, which could result in an electrical short and potential loss 
of several functions essential for safe flight.

 (f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Floor Panel Sealing

    Within 24 months after the effective date of this AD: Modify the 
floor panels; remove drains; install floor supports, floor drain 
trough doublers, drain troughs, and drains; and seal and tape the 
floor panels; at the applicable locations; in accordance with the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 747-25-3586, dated November 12, 2010.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in the Related Information 
section of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(i) Related Information

    For more information about this AD, contact Francis Smith, 
Aerospace Engineer, Cabin Safety & Environmental Systems Branch, 
ANM-150S, Seattle Aircraft Certification Office (ACO), FAA, 1601 
Lind Avenue SW., Renton, Washington 98057-3356; phone: 425-917-6596; 
fax: 425-917-6590; email: Francis.Smith@faa.gov.

(j) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Special Attention Service Bulletin 747-25-3586, dated 
November 12, 2010.
    (ii) Reserved.
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P. O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; phone: 
206-544-5000, extension 1; fax: 206-766-5680; Internet: https://www.myboeingfleet.com.
    (4) You may review copies of the referenced service information 
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., 
Renton, Washington. For information on the availability of this 
material at the FAA, call 425-227-1221.
    (5) You may also review copies of the service information that 
is incorporated by reference at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on August 22, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-21289 Filed 9-5-12; 8:45 am]
BILLING CODE 4910-13-P


